【摘要】 该文针对成对用户大规模MIMO中继系统,在中继采用最大比合并/最大比发射(MRC/MRT)预编码方案下,利用大数定律,推导出系统频谱效率的闭合表达式,显式的描述了频谱效率与中继天线数、用户对个数以及信源用户和中继发射功率的关系。基于此,分析了当天线数增大时,在用户对个数固定不变和等比例增长两种情况下,频谱效率的渐进性能和所能获得的发射功率增益。结果表明,当用户数固定时,频谱效率将随天线数呈近似对数增长规律;当用户数随天线数等比例增长时,通过调整比例值,可满足平均每个用户的频谱效率达到任意指定值,且无需额外发射功率消耗。最后,通过数值仿真验证了所推导的频谱效率闭合表达式的精确性以及所有渐进性能的分析结果。更多还原

【Abstract】 Based on the massive multiple-input multiple-output( MIMO) relaying system with multi-pair users,an analytical expression of the spectral efficiency was derived by virtue of the law of large numbers when the maximum ratio combining / maximum ratio transmission( MRC / MRT) precoding was adopted at the relay. The closed-form expression gave an explicit relation between the spectral efficiency and the number of relay antennas and user-pairs,as well as the transmit power at the source users and the relay. Using this expression,we analyzed the asymptotic performance of spectral efficiency and the transmit power gain when the number of relay antennas became large with the number of user-pairs keeping fixed or proportionally increasing. It was shown that the spectral efficiency increased with the number of relay antennas and decreased with number of user-pairs,both logarithmically. Moreover,when the number of served user-pairs increased proportionally to the number of relay antennas,arbitrary spectral efficiency per user could be achieved by adjusting the ratio of antenna number and user-pair number with no extra power cost. Numerical simulations validate the accuracy of the proposed closed-form expression of spectral efficiency and verify all the analytical results in the manuscript.更多还原